Pyrolytic conversion of hydrocarbons with recovery of coke



Jan. 17, 1950 R FISHER 2,494,695

r F. PYROLYTIC CONVERSION OF HYDROCARBONS WITH RECOVERY OF COKE Filed June 28, 1947 COKING CHAMBER i I a 9 l0 II I PRESSURE n', RELEASE CHAMBER \ELEVATOR I I INVENTOR l FRANK R. Fl-SHER MW ATTORNEYS Patented Jan. 17, 19 50 PYROLYTIC CONVERSION OF HYDROCAR- BONS WITH RECOVERY OF COKE Frank R. Fisher, Hammond, Ind., assignor to Sinclair Refining Company, New York, N. Y., a

corporation of Maine Application June 28, 1947, Serial No. 757,822

2 Claims. 1

The present invention relates to the menufacture of petroleum coke by the pyrolysis of hydrocarbons and provides an improved process adapted to continuous operation and comprising the introduction of a hydrocarbon feed stock, for instance, reduced crude, or heavy residual stock, into an enclosed coking chamber and, there, bringing the feed stock into contact with highly heated metal balls of steel, iron, or similar substance of relative impermeability. The coking chamber and the metal balls therein, are maintained at the coking temperature of the hydrocarbon feed stock, for instance, at a temperature within the range of 800 to Lilli) F. and at a relatively high superatmosphcric pressure, for instance, of the order of 100 to 500 pounds per square inch.

The chamber is, with advantage, filled with the balls and the feed stock is introduced into an intermediate zone of the chamber. Under these conditions, a heavy deposit of coke is formed on the surface of the balls. superheated steam is, with advantage, introduced into a lower zone of the chamber for the purpose of drying the coke deposit on the ball.

The balls, with the coke deposited thereon, gravitate downwardly through the coking chamher and are withdrawn from the lower end thereof, while other balls, substantially free from coke, are introduced into the upper end of the chamber. The movement of the balls through the coking chamber may be continuous, but for simplicity of operation, sealing the chamber at the exit and entrance of the balls, for instance, I prefer to move the balls through the chamber intermittently.

The halls pass from the lower end of the coking chamber, advantageously by gravity, into a lower chamber under approximately equal pressure. In the intermittent method of operation. the lower chamber is charged with the coke laden balls, while under pressure and thereafter the pressure within the chamber is suddenly released. This sudden release in pressure results in the rapid expansion of gases trapped in the pores of the coke and the breaking of the coke away from the surface of the balls.

advantageously, super-steam is also injected into the lower chamber, after the pressure has been released, to effect the further drying of the coke. The released gases and the steam from the lower chamber are. with advantage, passed to a recovery system for recovery of the hydrocarbon constituents.

Thereafter, the balls and the separated coke are withdrawn from the lower chamber, advantageously by gravity, and fall onto a heavy screen of a mesh such that the balls are retained on the screen while the coke passes through the screen. Advantageously, the coke passing from the lower chamber, is sprayed with water to reduce its temperature, and the balls are returned to the upper end of the coking chamber. Prior to the: return of the balls to the coking chamber, they are, with advantage, freed from residual coke and preheated to the coking temperature of the charge oil.

The invention will be further described and illustrated with reference to the accompanying drawing, which represents. conventionally and somewhat diagrammatically, a vertical section of apparatus particularly adapted to the carrying out of my invention.

The apparatus indicated in the drawing by the reference numeral l is a vertically elongated cylindrical chamber, closed at its upper end and divided at an intermediate point by hopper 2 and rotary valve 3 to form an upper coking chamber 4 and a lower pressure release chamber '5. The pressure release chamber is, in turn, closed at its lower end by hopper 6 and a rotary valve 1.

In operation, the coking chamber 4 is filled with highly heated balls and the charging oil, reduced crude, for instance, is injected into an intermediate portion of the chamber through line 8 in which there is interposed a valve 9. The chamber 4 is under a super-atmospheric pressure of to 500 pounds per square inch and at a temperature of 800 to 1,100 F., and the: charge oil is injected thereto until a heavy coke deposit is formed on the hot metal balls. Thereafter, the charging of the oil is discontinued by closing valve 9 and superheated steam is injected into the chamber through line In, in which there is interposed a valve II, for the purpose of drying the coke. Eilluent vapors and gases pass from the upper end of the chamber through line I! in which there is interposed a valve l3, by which the pressure is maintained on the chamber 4.

Thereafter, the rotary valve 3 is turned to the open position, and the balls with the coke thereon are permitted to fall into the lower chamber 5, also maintained under a high pressure. The valve 3 is then turned to the closed position and the pressure on chamber 5 suddenly released by opening valve II in line I5. As a result of the sudden release of the pressure, the coke is broken from the surface of the balls by the expanding gases contained in the coke and superheated steam is injected into the lower end of the chamber through line "5, in which there is interposed a valve H, for the further drying of the coke.

After the coke has been sufliciently dried, the valve '5 is turned to the open position and the metal balls, together with the coke broken therefrom, fall onto the heavy inclined screen 63, of such mesh as to permit the coke to fall therethrough onto the conveyor B9. The coke falling from the chamber onto the screen it is, with advantage, sprayed with water, introduced through valved line 29 and the sprayhead 2i, for the purpose of cooling the coke.

The balls, separated from the coke, roll down the inclined screen 03 and enter the lower end of elevator 22 by which they are carried upwardly into the chamber 23. In chamber 23, the balls, which contain some residual coke deposit, are blown with preheated air, introduced through line 26, whereby residual coke is burned from the balls and the balls thereby heated and the products of combustion pass from chamber 23 through flue 25. 7

After the residual coke has been burned from the balls, the gate valve 23, in line 27, is opened and the balls are permitted to fall therethrough into chamber 23. The valve is then closed and superheated steam, or other suitable gas, is injected into chamber 28 through valved line 29, until the pressure within chamber 28 is equal to, or slightly higher than, that maintained in the coking chamber 8. The gate valve 33, in line 3i, is then opened and the balls are permitted to pass therethrough into the coking chamber. The valve 30 is then closed and the pressure in chamber 28 released through valved line 32.

From the foregoing description, it will appear that the steel balls are repeatedly passed through the system, the balls passing from chamber to chamber intermittently.

I claim:

1. A process for the production of petroleum coke which comprises passing a hydrocarbon charge oil in contact with a bed of metal balls maintained at the coking temperature of the 'charge oil, and under a superatmospheric pressure of to 500 pounds per square inch, until a heavy deposit of coke is termed on the surface or the metal balls, thereafter suddenly releasing the pressure whereby the coke is broken by the explosive forces of expending gases contained in the pores of the coke and separating the coke from the metal balls.

2. A process for coking hydrocarbons which comprises maintaining a body of metal balls in a chamber under superatmospheric pressure and at a temperature at least as high as the coking temperature of the hydrocarbons, passing the hydrocarbons to be coked in contact with the metal balls until a heavy coke deposit has formed on the surfaces of the balls, thereafter suddenly releasing the pressure whereby the coke is broken by the explosive forces of expanding gases contained in pores of the coke and separating the coke from the metal bails.

FRANK R. FISHER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,698,345 Puening Jan. 8, 1929 1,712,082 Koppers May 7, 1929 1,712,083 Koppers May 7, 1929 2,274,003 Sheppard Feb. 24, 1942 2,304,398 Campbell Dec. 8, 1942 2,357,570 Adams Sept. 5, 1944 2,373,043 Mayer Apr. 3, 1945 

1. A PROCESS FOR THE PRODUCTION OF PETROLEUM COKE WHICH COMPRISES PASSING A HYDROCARBON CHARGE OIL IN CONTACT WITH A BED OF METAL BAILS MAINTAINED AT THE COKING TEMPERATURE OF THE CHARGE OIL, AND UNDER A SUPERATMOSPHERIC PRESSURE OF 100 TO 500 POUNDS PER SQUARE INCH, UNTIL A HEAVY DEPOSIT OF COKE IS FORMED ON THE SURFACE OF THE METAL BALLS, THEREAFTER SUDDENLY RELEASING THE PRESSURE WHEREBY THE COKE IS BROKEN BY THE EXPLOSIVE FORCES OF EXPENDING GASES CONTAINED IN THE PORES OF THE COKE AND SEPARATING THE COKE FROM THE METAL BALLS. 